1. Field of the Invention
The present invention relates to a dry-etching method for patterning metallic film made from aluminum for example into an optional configuration.
2. Description of the Prior Art
Dry etching processes are used against metallic electrode film and semiconductor film of a semiconductor. In particular, reflecting extremely severe requirements in conjunction with manufacture of integrated circuits into extremely fine configuration, it is essential for the manufacturers to implement plasma etching such as reactive ion etching for example. As was disclosed in the Japanese Patent Laid-Open No. 61-41132 (1986), while holding the objective material in reactive gas environment, plasma is first activated by radio-frequency discharge to generate a variety of ions and radicals before etching is eventually executed by multiple function of sputter effect generated by collision of ions and chemically reactive radicals.
Nevertheless, as mentioned above, since the plasma etching cannot be achieved merely by chemical reaction of radicals, but by multiple function of sputter effect generated by collision of ions, the plasma etching incurs physical damage to the surface of the etched object. If the etched object has minimal configuration like a semiconductor device, the adverse effect of physical damage cannot be ignored at all.
On the other hand, although it is considered that any conventional dry etching method directly irradiating focussed ion beams to the target portion of the etching object is quite promising, since this method also sputters the objective etching portion with focussed ion beams, the remaining portion of the etched surface unavoidably incurs certain physical damage.